Digital cameras can capture still images when a user manipulates a shutter button. Manipulation of the shutter button can signal a processor in the digital camera to move a shutter mechanism, similar to what occurs in non-digital cameras, to allow light to impinge on a digital imaging device, typically a charge-coupled device (CCD). The CCD in turn converts light into electric signals that are sent to the processor for generating an image. Or, in some digital cameras, opening a lens cover and activating the camera allows light to impinge on the CCD, with the signals from the CCD being used to generate a video stream of images and with manipulation of the shutter button not necessarily causing actuation of a shutter mechanism but instead signalling to the processor to “grab” one of the images in the stream as a still image. Accordingly, regardless of whether manipulation of the shutter button actually causes a shutter mechanism to “expose” the CCD or simply causes an image in a stream of images to be “grabbed”, it is to be appreciated that the user establishes a still image by manipulating the shutter button to cause the processor to capture a still image.
As recognized by the present invention, digital cameras can suffer many of the same drawbacks as non-digital camera when taking a picture, namely, causing a still image to be generated at a less than opportune time for the subject. For example, the still image might be generated at the instant the subject blinks, or fails to smile. In other contexts, it might be desired to take an action photo of a sporting event, but it can be difficult, giving the fast-moving nature of the game, to generate a still image at an action point at precisely the moment the action occurs. Thus, for instance, a still image of a soccer match, instead of being generated just as the ball pierces the plane of the goal, might not be generated until the ball is already in the net. In any case, it may be appreciated that the present invention recognizes that it would be advantageous to couple the generation of a still image to one or more criteria that are subject-dependent.